Add shutdown_worker_rejected field to poll responses

proto/internal/temporal/server/api/matchingservice/v1/request_response.proto

@@ -64,6 +64,9 @@ message PollWorkflowTaskQueueResponse {
     // Raw history bytes sent from matching service when history.sendRawHistoryBetweenInternalServices is enabled.
     // Matching client will deserialize this to History when it receives the response.
     temporal.api.history.v1.History raw_history = 22;
+    // When true, this empty response was caused by the server rejecting the poll
+    // because the worker has been shut down via the ShutdownWorker API.
+    bool shutdown_worker_rejected = 23;
 }
 
 // PollWorkflowTaskQueueResponseWithRawHistory is wire-compatible with PollWorkflowTaskQueueResponse.
@@ -114,6 +117,9 @@ message PollWorkflowTaskQueueResponseWithRawHistory {
     // When matching client deserializes this to PollWorkflowTaskQueueResponse, this field
     // will be automatically deserialized to the raw_history field as History.
     repeated bytes raw_history = 22;
+    // When true, this empty response was caused by the server rejecting the poll
+    // because the worker has been shut down via the ShutdownWorker API.
+    bool shutdown_worker_rejected = 23;
 }
 
 message PollActivityTaskQueueRequest {
@@ -151,6 +157,9 @@ message PollActivityTaskQueueResponse {
     temporal.api.common.v1.RetryPolicy retry_policy = 19;
     // ID of the activity run (applicable for standalone activities only)
     string activity_run_id = 20;
+    // When true, this empty response was caused by the server rejecting the poll
+    // because the worker has been shut down via the ShutdownWorker API.
+    bool shutdown_worker_rejected = 21;
 }
 
 message AddWorkflowTaskRequest {
@@ -585,6 +594,9 @@ message PollNexusTaskQueueRequest {
 message PollNexusTaskQueueResponse {
     // Response that should be delivered to the worker containing a request from DispatchNexusTaskRequest.
     temporal.api.workflowservice.v1.PollNexusTaskQueueResponse response = 1;
+    // When true, this empty response was caused by the server rejecting the poll
+    // because the worker has been shut down via the ShutdownWorker API.
+    bool shutdown_worker_rejected = 2;
 }
 
 message RespondNexusTaskCompletedRequest {

service/frontend/workflow_handler.go

@@ -988,6 +988,8 @@ func (wh *WorkflowHandler) PollWorkflowTaskQueue(ctx context.Context, request *w
 		Queries:                    matchingResp.Queries,
 		Messages:                   matchingResp.Messages,
 		PollerScalingDecision:      matchingResp.PollerScalingDecision,
+		// TODO: propagate ShutdownWorkerRejected once go.temporal.io/api is bumped
+		// to include the new field: matchingResp.ShutdownWorkerRejected
 	}, nil
 }
 
@@ -1225,6 +1227,8 @@ func (wh *WorkflowHandler) PollActivityTaskQueue(ctx context.Context, request *w
 		PollerScalingDecision:       matchingResponse.PollerScalingDecision,
 		Priority:                    matchingResponse.Priority,
 		RetryPolicy:                 matchingResponse.RetryPolicy,
+		// TODO: propagate ShutdownWorkerRejected once go.temporal.io/api is bumped
+		// to include the new field: matchingResponse.ShutdownWorkerRejected
 	}, nil
 }
 
@@ -5641,6 +5645,8 @@ func (wh *WorkflowHandler) PollNexusTaskQueue(ctx context.Context, request *work
 		return nil, err
 	}
 
+	// TODO: propagate matchingResponse.ShutdownWorkerRejected to the public
+	// PollNexusTaskQueueResponse once go.temporal.io/api is bumped.
 	return matchingResponse.GetResponse(), nil
 }